It is known that thiocyanogen is an active compound useful for treating the surfaces of polymers to enhance the adhesion of paint applied thereto. Thiocyanogen is also useful in reacting with organic compounds to prepare organic thiocyanates or isothiocyanates.
The reaction with the polymers or with organic compounds is advantageously conducted in solution since the thiocyanogen is not normally isolable as such. Even in solution, however, the thiocyanogen is not stable and will precipitate from solution as a polymeric material which is unreactive for the purposes desired. Thus, these solutions must be used within a short period of time after preparation. Therefore, it would be highly desirable to develop a stable form of such solutions to enable them to be shipped and to be used at a time somewhat later than the time at which they are prepared.
Thiocyanogen is prepared by methods known to the art. Metal thiocyanates are oxidized, e.g. reacted with Cl.sub.2, to form the thiocyanogen, (SCN).sub.2. Illustrative of this reaction is the use of potassium thiocyanates: EQU 2KSCN+Cl.sub.2 .fwdarw.(SCN).sub.2 +2KCl
The thiocyanates of metals of Groups IA, IIA, and IVA of the periodic chart are also useful. Examples are the thiocyanates of sodium, lithium, potassium, calcium and lead.
Oxidizing agents which can be used in place of chlorine are bromine, fluorine and organic peroxides.
A thiocyanating composition has now been discovered which has the desirable properties of the unstable thiocyanogen, but in which the tendency to polymerize is inhibited, allowing it to remain active over long periods of time.